Introduction: Self-adhesive resin composite (SARC) is gaining popularity due to its simplified clinical steps. The objectives of this study were to evaluate the bonding performance, mass stability and mechanical properties of three SARCs and to compare them with two conventional resin composites (RCs) using a universal adhesive system (UAS).

Materials and Methods: A total of 80 enamel blocks, 5 mm x 5 mm, were prepared and embedded in an acrylic mold. The surface of enamel was polished using 600-grit carbide paper to create a smear layer. After acid etching, a 2mmX2mm cylinder-shaped restoration was made either with one of three SARC materials or with two types of RC using UAS. The shear bond strength test was performed after 24 h of water incubation and after 1 year of artificial aging. The mass stability of the hexagonal-shaped SARC and conventional RC was evaluated using water sorption and solubility tests. The mechanical properties, including Vickers hardness, elastic modulus and creep, were evaluated after 24 h of water incubation and after 1 year of artificial aging.

Results: Both material type and aging showed a significant effect on bonding performance, mass stability and mechanical properties of SARC and conventional RC (p<0.05). The shear bond strength of SARC was comparable to that of conventional RC+ UAS. Conventional RC showed less water sorption and solubility compared to SARC. The Vickers hardness, elastic modulus and creep properties of some SARC were inferior compared to those of conventional RC both at 24 h and at 1 year.

Conclusion: The bonding performance of SARC can substitute for that of conventional RC+ UAS; however, inferior mass stability and mechanical properties limit its use in routine dental restorative procedures.